Print on demand sellers need a mockup for every product variant. Photographing each one on every available colour is impractical. The workflow that works is to photograph once, cut out the garment, and composite the design over it digitally.
Flat-lay or ghost mannequin. Even lighting. Any background works because it is being replaced.
Download the PNG with alpha. The cutout preserves the garment silhouette and any visible texture at the edges.
Use the editor or an external design tool to place your artwork over the shirt. Adjust the blend mode to multiply so fabric texture shows through the design.
Amazon and Etsy both accept 2000 pixels on the long side. Export PNG with transparency if you want to composite over different backgrounds later.
The tool preserves what is visible at the edges of the garment. The interior texture is whatever was photographed. If you are compositing a design over it, the design will look flat unless you use a blend mode that lets the texture through.
Yes. The same workflow applies to any print on demand product. Photograph the blank once, cut it out, and composite designs over it.
On-model photos with models cut out are possible but harder because the model needs to be preserved too. For most print on demand workflows, ghost mannequin or flat-lay photos work better.